“It is not the most lighthearted way to start a weekend in the Hamptons, but it is relevant,” said Oliver Niedermaier, who hosted the party with his wife, Constanze, to draw attention to the issue of slavery in the modern world.

Last year, Roger Waters showed up at Amagansett's Stephen Talkhouse when G.E. Smith was playing, Nick Kraus, a manager there, said. He missed it, unfortunately, he said, "Pink Floyd was there and I was nearby and had no idea." Anyway, he is surprised that tonight's 8 p.m. show, which will include Taylor Barton, has not yet sold out.

Mr. Kraus also couldn't believe there were still tickets for Xavier Rudd's show on Thursday night, a popular performer he called an "Australian Jack Johnson."